Contribution of small airway inflammation to the development of COPD.

"Declarations Ethics approval and consent to participateAll patients signed informed consent forms, and the study was approved (B2018-010R) by the Ethics Committee of Zhongshan Hospital, Fudan University, in accordance with the Declaration of Helsinki. Consent for publicationNot applicable. Conflict of interestThe authors report no conflicts of interest. Conflict of interest The authors report no conflicts of interest."

"Funding This study was supported by the National Key R&D plan, number: 2020YFC2003700; the Shanghai Municipal Key Clinical Specialty, number: shslczdzk02201; The Construction of Multidisciplinary Cooperative Diagnosis and Treatment for Severe Pneumonia, number: W2020-013; The Mechanisms of Antibiotic Resistance in Severe Pneumonia Treated with Traditional Chinese and Western Medicine, number: ZY (2021–2023)-0207-01; Multi-dimensional Model in Standardized Training of Respiratory and Critical Medical Specialists, number: FDYXYBJ-20222009, and the Science and Technology Commission of Shanghai Municipality, number: 20DZ2261200."